40 Questions
What is the primary cause of cancer in the human body?
An uncontrolled division of abnormal cells in a part of the body
What type of cancer arises from connective tissue found in bones, tendons, cartilage, muscle, and fat?
Sarcoma
What is the effect of an activating mutation on a gene?
It causes the gene to be expressed at the wrong time, at the wrong level, or with a new function
What type of mutation is inherited from a parent and can increase the risk of certain cancers?
Germline mutation
According to the Two Hit Hypothesis, what happens if one copy of a gene is mutated?
The other copy of the gene allows the protein to operate normally
What is the increased risk for women who inherit a BRCA1/2 mutation?
Breast cancer
What is the effect of an inactivating mutation on a gene?
It causes reduced function of the gene
What is the primary location where leukemia arises?
Bone marrow
What is required for a gene to be cancer-inducing?
Both copies of the gene must be affected
What is the primary reason why normal human cells have a finite ability to undergo mitosis?
Due to the shortening of telomeres after each mitotic division
What is the function of the tumor suppressor gene p53?
To stop the cell cycle upon detection of DNA damage
Why do cancer cells avoid normal growth suppressor signals in the G1 checkpoint?
To continue proliferating
What is the result of normal cells breaking down glucose through glycolysis?
The cell produces energy in the form of ATP
What is the advantage of cancer cells diverting metabolites from glycolysis?
It allows the cell to divert metabolites for useful processes such as mitosis
How do cancer cells maintain their ability to proliferate?
Due to the aforementioned Hallmarks 1-4 as well as over-active oncogenes
What is the primary difference between normal cells and cancer cells in terms of telomeres?
Cancer cells are able to elongate their telomeres
What is the primary function of the immune system?
To surveil the body and destroy foreign cells and pathogens
What is the purpose of PDL-1 and PDL-2 antigens in cancer cells?
To inhibit T cells that would normally attack cancer cells
What is the term for the process by which tumor cells move from the primary tumor to a different organ?
Metastasize
What is the difference between benign and malignant tumors?
Benign tumors are unable to invade neighboring tissue or metastasize, while malignant tumors can
What is the term for multiple metastatic tumors?
Metastases
What is the result of primary tumor growth?
Cells grow uncontrollably until they become a mass, but some can remain benign
What is a common site for secondary tumors?
Lung and liver
What is a danger of metastasis?
All of the above
What is the core idea behind the scientific theory of evolution?
All living organisms on Earth descended from a common ancestor
What is adaptation in the context of evolution?
A trait that improves an organism's change for survival and reproduction
What happens to organisms with traits that help them survive and reproduce?
They pass their characteristics to their offspring
What is heritability in the context of evolution?
The passing of traits from parents to offspring
What is the outcome of natural selection?
Helpful traits survive and spread through the population
What is the estimated percentage of species that have ever lived on Earth that have become extinct?
99.9%
What is the average lifespan of a species?
2-10 million years
What is gradualism in the context of evolution?
The idea that species originate through a gradual change of adaptations
What is the main idea behind the punctuated equilibrium hypothesis?
Speciation occurs rapidly, with long periods of genetic equilibrium in between
What is the approximate timeframe for rapid speciation events according to punctuated equilibrium?
10,000 years or less
What is genetic engineering?
The process of changing the DNA in living organisms to create something new
What is the main goal of selective breeding?
To produce offspring with desired traits
What is an example of hybridization?
Crossing a disease-resistant plant with one that has a large food-producing capacity
What is the main risk of inbreeding?
Increased chance of genetic disorders
What is cloning?
The process of creating an organism that is an exact genetic copy of another
What is the relationship between genetic engineering and genetically modified organisms (GMOs)?
GMOs are a type of genetic engineering
Study Notes
What is Cancer?
- Cancer is caused by an uncontrolled division of abnormal cells in a part of the body
- Caused by an accumulation of detrimental variations in the genome over a lifetime
Types of Cancer
- Carcinoma: arises in epithelial tissue in internal and external linings of the body
- Adenocarcinomas develop in organs or glands
- Squamous cell carcinomas develop in squamous epithelium of organs, including skin, bladder, esophagus, and lung
- Sarcoma: arises from connective tissue in bones, tendons, cartilage, muscle, and fat
- Leukemia: cancers of the blood that originate in bone marrow
- Lymphoma: cancers of the lymph system
Mutations
- Activating mutations: cause genes to be expressed at the wrong time, level, or function
- Inactivating mutations: reduce function of a gene (less RNA or protein is made)
- Somatic mutations: acquired by somatic cells (all cells except eggs or sperm) and passed to daughter cells
- Germline mutations (inherited mutations): present in germ cells (eggs or sperm) and inherited by offspring
Two Hit Hypothesis
- Humans have two copies of every gene (diploid): one maternal, one paternal
- Both copies of the gene must be affected for a gene to be cancer-inducing
Cellular Hallmarks of Cancer
- Normal human cells have a finite ability to undergo mitosis due to telomere shortening
- Cancer cells can exceed Hayflick's limit and continue to undergo mitosis
- Cancer cells elongate telomeres using telomerase
- Cancer cells avoid normal growth suppressor signals in the G1 checkpoint
- Tumor suppressor genes, like p53, regulate cell death and proliferation
- Cancer cells have altered metabolism, proliferating and diverting metabolites for useful processes
- Cancer cells evade immune surveillance and can inhibit T cells with PDL-1/PDL-2 antigen
Metastasis
- The process by which tumor cells move from the primary tumor to a different organ via lymph and/or blood
- Benign tumors are masses of cells that cannot invade neighboring tissue or metastasize
- Malignant tumors are capable of invading neighboring tissue and metastasizing
- Dangers of metastasis include treatment for pain, and the need for ongoing treatment
Evolution
- The scientific theory that all living organisms on Earth descended from a common ancestor
- Principles of Darwinian Evolution: variation, heritability, overproduction, reproductive advantage, and adaptation
- Natural Selection: organisms with traits that help them survive and reproduce pass their characteristics to their offspring
- Variation exists among individuals within a population
- Extinction is a natural and important part of evolution
Genetic Engineering
- Changing the DNA in living organisms to create something new
- Genetically Modified Organisms (GMOs) are the result of genetic engineering
- Artificial selection: breeders choose which organisms to mate to produce offspring with desired traits
- Hybridization: crossing two individuals with unlike characteristics to produce the best in both organisms
- Inbreeding: breeding of organisms that are genetically similar to maintain desired traits
This quiz covers the causes and main types of cancer, including carcinoma, adenocarcinoma, and squamous cell carcinoma.
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